I need help with imprint stones: i tried to search for info but i couldnt find anyone that was in depth

So

I have only been playing maybe 1 month

I have 6 guys at awaken level 2 (nests kyo and the rest of the starter mission guys and ss chizuru)

None of them have imprint stones yet

I read that you cannot detatch an imprint stone so i want to be careful doing this

Any help from anyone is appreciated

My questions:

1. So the game warned me i cannot detatch an imprint stone from a character - does that mean i cannot replacr the imprint stone, or that i can replace the imprint stone, but the 1st one is lost?

2. Can i enhance an imprint stone thats already attached to a character?

3. I really dont know about imprint stones - is there a way to make them stronger beside enhancement hammers (like combining stones)?

4. Is there a salvage function for the stone? If there is - what does it do? (Does it allow you to craft stones you want to craft?)

Thanks a lot in advance for any help